# !!! warning "Experimental implementation (upwind SBP)"
#     This is an experimental feature and may change in future releases.

using OrdinaryDiffEqLowStorageRK
using Trixi

###############################################################################
# semidiscretization of the compressible Euler equations
equations = CompressibleEulerEquations3D(1.4)

initial_condition = initial_condition_convergence_test

D_upw = upwind_operators(SummationByPartsOperators.Mattsson2017,
                         derivative_order = 1,
                         accuracy_order = 4,
                         xmin = -1.0, xmax = 1.0,
                         N = 16)
flux_splitting = splitting_steger_warming
solver = FDSBP(D_upw,
               surface_integral = SurfaceIntegralUpwind(flux_splitting),
               volume_integral = VolumeIntegralUpwind(flux_splitting))

coordinates_min = (0.0, 0.0, 0.0)
coordinates_max = (2.0, 2.0, 2.0)
mesh = TreeMesh(coordinates_min, coordinates_max,
                initial_refinement_level = 2,
                periodicity = true)

semi = SemidiscretizationHyperbolic(mesh, equations, initial_condition, solver;
                                    source_terms = source_terms_convergence_test,
                                    boundary_conditions = boundary_condition_periodic)

###############################################################################
# ODE solvers, callbacks etc.

tspan = (0.0, 1.0)
ode = semidiscretize(semi, tspan)

summary_callback = SummaryCallback()

analysis_interval = 100
analysis_callback = AnalysisCallback(semi, interval = analysis_interval)

alive_callback = AliveCallback(analysis_interval = analysis_interval)

save_solution = SaveSolutionCallback(interval = 100,
                                     save_initial_solution = true,
                                     save_final_solution = true,
                                     solution_variables = cons2prim)

stepsize_callback = StepsizeCallback(cfl = 1.1)

callbacks = CallbackSet(summary_callback,
                        analysis_callback, alive_callback,
                        save_solution,
                        stepsize_callback)

###############################################################################
# run the simulation

sol = solve(ode, CarpenterKennedy2N54(williamson_condition = false);
            dt = 1, # solve needs some value here but it will be overwritten by the stepsize_callback
            ode_default_options()..., callback = callbacks);
